Add a button for instructions on how to add a jupyter notebook from the SessionViewer to the plugin store

[ewuerger]

When a user has developed a nice routine in a Jupyter notebook and she wants to reuse and execute this regurlary the best way should be to make a Plugin out of it. So having a button How to add this notebook as a plugin which opens a dialog with steps on how to create a mbse works plugin with this routine would be cool.

[MoritzWeber0]

Since we're far away from having a plugin store at all, I'll close this issue to keep the list of issues clean. The current implementation status is tracked in this PR: #722